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Analysis of nucleic acid double helix geometry

Title CRYSTAL STRUCTURE OF RUNX-1/AML1/CBFALPHA RUNT DOMAIN- CBFBETA CORE DOMAIN HETERODIMER AND C/EBPBETA BZIP HOMODIMER BOUND TO A DNA FRAGMENT FROM THE CSF-1R PROMOTER
PDB code 1IO4   (PDB summary)
NDB code PD0198 (NDB atlas)
Duplex length 25 base pairs
Protein Aml1/Runx-1 Runt Cbfbeta, Transcription Factor

Only the nucleic acid double helix part of the structure is analysed here. Small ligands, proteins, and overhanging ends are not taken into account. Information on the complete structure is available at the Image Library Entry page and at the Sequence, Chains, Units page.

Strand 1    5' A2 A3 G4 A5 T6 T7 T8 C9 C10 A11 A12 A13 C14 T15 C16 T17 G18 T19 G20 G21 T22 T23 G24 C25 G26 3'
Strand 2    3' T26 T25 C24 T23 A22 A21 A20 G19 G18 T17 T16 T15 G14 A13 G12 A11 C10 A9 C8 C7 A6 A5 C4 G3 C2 5'

Side view 1 Top view
Side view 1 Top view
Side view 2 3-dimensional interactive models
(Help)
  

RASMOL, CHIME, VRML 2.0, PDB

Side view 2  

Figure 1   Three orthogonal views of the double helix (Help). Residues are colored according to the nucleotide type (Help: Color codes). The curvilinear helical axis (green) was calculated with CURVES. The double helix is oriented with respect to the principle axis of inertia of the curvilinear helical axis (see Help for further explanations). This drawing reveals immediately if there is any bending of the helical axis.


Analysis of helical axis bending


Inter base pair parameters

The six inter base pair parameters (rise, shift, slide, twist, roll, tilt) describe the translational and rotational displacement between neighbouring base pairs. See Help for further explanations.

Plot of inter base pair parameters with respect to global and local helical axes:  PDF,   GIF
(Global parameters from CURVES,  local parameters from CURVES and FREEHELIX)

Table 1.  Inter base pair parameters with respect to the global helical axis, calculated with CURVES.


  Strand 1      Strand 2        riseg          shiftg          slideg          twistg         rollg         tiltg    
    / Å / Å / Å      

A2 T26            
    3.2 -0.9 0.8 38° -12° -4°
A3 T25            
    3.2 0.3 -0.1 38° -3° -2°
G4 C24            
    3.2 -0.2 -0.2 38° -2° -2°
A5 T23            
    3.0 -0.6 -0.7 32° -2°
T6 A22            
    3.5 0.5 -0.1 34° -5°
T7 A21            
    3.1 -0.2 0.1 37° -3°
T8 A20            
    3.3 -0.3 -0.3 40° -1°
C9 G19            
    3.3 0.7 0.1 34°
C10 G18            
    3.3 -0.7 -0.1 28° -0°
A11 T17            
    3.0 0.0 0.5 34° -2°
A12 T16            
    3.2 -0.1 0.2 35° -2°
A13 T15            
    3.2 0.2 -0.6 31° -0°
C14 G14            
    3.6 -0.4 -0.4 35° -4°
T15 A13            
    3.4 0.6 0.1 40°
C16 G12            
    3.2 -0.6 -0.1 28°
T17 A11            
    3.6 0.8 0.6 41° -5°
G18 C10            
    3.0 -1.0 -0.2 26° -3° -4°
T19 A9            
    3.2 0.2 -0.1 34° -3° -0°
G20 C8            
    3.3 -0.5 -0.0 34° -3°
G21 C7            
    3.2 0.9 -0.7 30°
T22 A6            
    3.3 0.0 -0.5 34°
T23 A5            
    3.1 -0.6 1.2 37°
G24 C4            
    3.0 0.1 -0.6 34° -3°
C25 G3            
    3.2 0.2 0.1 35° -3°
G26 C2            


Backbone parameters

Table 2.  Selected torsional angles and sugar pucker phase angles describing the conformation of the sugar phosphate backbone. (See Help for further explanations.)


 gamma     epsilon-zeta       pucker        chi      Strand 1     Strand 2      chi        pucker       epsilon-zeta     gamma 

    C2'-endo -82° A2 T26 -73° C2'-endo    
 41°   70° (BII)             -98° (BI)   -50° 
    C3'-exo -94° A3 T25 -94° C3'-exo    
 44°   -82° (BI)             -63° (BI)   -16° 
    C2'-endo -93° G4 C24 -101° C3'-exo    
 49°   -83° (BI)             -63° (BI)   -71° 
    C2'-endo -95° A5 T23 -114° C2'-endo    
 30°   -103° (BI)             -54° (BI)   -161° 
    C2'-endo -90° T6 A22 -133° C2'-endo    
 28°   -98° (BI)             -57° (BI)   -60° 
    C2'-endo -99° T7 A21 -101° C3'-exo    
 43°   -77° (BI)             -57° (BI)   175° 
    C2'-endo -101° T8 A20 -145° C3'-exo    
 8°   -78° (BI)             -115° (BI)   47° 
    C3'-exo -101° C9 G19 -114° C2'-endo    
 -86°   -65° (BI)             -39° (BI)   25° 
    C3'-exo -115° C10 G18 -79° C2'-endo    
 11°   -64° (BI)             -93° (BI)   30° 
    C3'-exo -99° A11 T17 -79° C2'-endo    
 33°   -92° (BI)             -97° (BI)   26° 
    C3'-exo -79° A12 T16 -92° C3'-exo    
 35°   -91° (BI)             -106° (BI)   -54° 
    C2'-endo -90° A13 T15 -110° C3'-exo    
 -98°   -46° (BI)             -74° (BI)   -61° 
    C2'-endo -121° C14 G14 -109° C3'-exo    
 59°   -88° (BI)             -53° (BI)   71° 
    C2'-endo -111° T15 A13 -122° C2'-endo    
 -1°   -72° (BI)             -71° (BI)   -54° 
    C3'-exo -103° C16 G12 -76° C3'-exo    
 4°   -87° (BI)             -49° (BI)   -170° 
    C3'-exo -86° T17 A11 -139° C2'-endo    
 44°   -96° (BI)             83° (BII)   11° 
    C2'-endo -111° G18 C10 -74° C2'-endo    
 34°   -62° (BI)             -115° (BI)   -58° 
    C2'-endo -101° T19 A9 -112° C3'-exo    
 -70°   -44° (BI)             -58° (BI)   2° 
    C3'-exo -112° G20 C8 -112° C3'-exo    
 36°   -82° (BI)             -95° (BI)   -31° 
    C2'-endo -104° G21 C7 -126° C3'-exo    
 -73°   -58° (BI)             -60° (BI)   -80° 
    C2'-endo -113° T22 A6 -131° C3'-exo    
 -72°   -52° (BI)             -48° (BI)   42° 
    C3'-exo -126° T23 A5 -78° C2'-endo    
 179°   -37° (BI)             -99° (BI)   26° 
    C3'-exo -123° G24 C4 -96° C3'-exo    
 -3°   -100° (BI)             -91° (BI)   46° 
    C3'-exo -94° C25 G3 -96° C2'-endo    
 162°   -111° (BI)             -77° (BI)   30° 
    C3'-exo -138° G26 C2 -107° C3'-exo    


Groove width

Plot of minor groove width:   PDF,   GIF
Plot of major groove width:   PDF,   GIF
(See Help for further explanations.)

Further information

Full output from CURVES  (helical parameters with respect to global and local axes)

Full output from FREEHELIX  (helical parameters with respect to local axis, angles between normal vectors)

Chirality of ribose and phosphate atoms
Check the naming of phosphate and ribose substituents. Recommended for phosphate oxygens and for ribose hydrogens in NMR structures.


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Perl script:    helixparameter.pl  (15 Sep 2016)
Author:    Peter Slickers  (slickers@leibniz-fli.de),  IMB Jena,  Germany